Seriously, what else was Tedd afraid of? Having it just not work wouldn't be that bad of a consequence. Maybe he was afraid it would override one of Grace's natural forms or something so she could be a squirrel-girl or a cat-girl, but not a human. Or possibly that all of her forms would be part kitty. Although come to think of it he's already done at least some testing on Will and Gill before this so he shouldn't have been that worried about it's effects on shapeshifters. Of course, the background of the TFG hasn't been established yet so their involvement and Tedd's reason for having the gun in the first place probably weren't thought of yet.
Well whatever was going on in Tedd's mind, Grace was definitely a bad kitty for performing a dangerous experiment like that. The question then is what's the best way to punish a naughty cat-girl, spray her with water or give her a spanking
